Simulation failed (diverge)

Hello there,

Although you helped me to find out the solution for fixing diverge issues during the simulation process, I can’t solve it. I tried to upgrade the mesh quality several times, but it constantly shows the divergence issues. I experience this for three times, I couldn’t finish this simulation for several days. In my previous uploads in Forum, simulation objective is clearly explained.

Please help me to solve this divergent issues, It is hard for me to treat the geometry, as for me Edit CAD with face move function doesn’t work well to delete the sharp face part at the end of the pipe region. If you can, then please help me. Please tell me the solutions with upgrading mesh quality if possible.

Best regards,
Kim

Hello Kim,
Can you please send a link to the project here in the forum, so that can have a look at it?

Thanks and best regards
Sebastian

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It was hard to make link address with the project,


I invited you to the project. As it is private geometry not to be public, please have a look through that invitation, if possible. Thank you so much.

Hi Kim,

in order to increase the quality of your mesh please try to remove most of the small feature details in your projects such as these two examples.

Example one, thin edge on the end of the pipe, here actually the divergency occurred.

Thin gap within the flow region, and small features.

Please try to start with a model which has only large features, you can later on add feature ins order to see the accuracy of your simulation.

Also you won’t need the perforated geometry, as this will be represented by the defined prouse media.
Here you also only need to assign the geometry primitve, so you can deselect the assigned volume.

Last, i guess you missed the assignment of the symmetry plane to the cutted part.
Please assign a symmetry boundary condition here:

Best regards
Sebastian

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Thank you! I will try. But I have another question - I need perforated volume structure because my project wants to compare the fluid flow situation with different hole sized of the perforated media. In that cases, should I abandon Darcy model?

Hi Kim.

it depends if you have test data for the Darchy-Forcheimer coefficients for each hole diameter,
or what the fines of the holes are.
For your example, i guess it’s okay to go with the direct approach, for anything smaller I would recommend using a model, as computational costs can get very high since a higher mesh fineness is needed.

Another option would be to use the perforated plate as explained here:

Best regards
Sebastian

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It was well solved! Many Thanks!!!